L-carnitine stimulates the transport of long-chain fatty acids across the inner mitochondria membrane to produce energy. It is synthesized with lysine and methionine as precursors. During lactation, the potential for biosynthesis of L-caritine in piglet has not yet developed, and so its supply depends on milk. The effects of L-carnitine supplementation to the feed of sows during pregnancy and lactation were demonstrated in earlier studies. The present study aimed to evaluate the effect of short-term L-carnitine supplementation in the following : on its concentration in milk during lactation, on the return of estrus, and on the growth performance of piglets. Fourteen crossbred sows with similar farrowing days were used at a commercial farm. They were classified into 2 groups ; a control group, in which sows were fed normal commercial feed ; and an L-carnitine-treated group, in which the feed included 50ppm of L-carnitine. Milking was conducted on days 0, 2, 3 and 11 after farrowing and the concentration of total, free and acetyl-form L-carnitine in milk were quantitatively analyzed. Milk yield was determined on days 1, 7, 14 and weaning by the weigh-suckle-weigh method. The number of piglets born, birth weight, deaths due to weakening, weaning weight, and the return date of estrus were recorded. The individual birth weight of piglets in the L-carnitine-treated group was significantly higher than that in the control group, but there was no significant difference in the litter weights at birth. Daily gain in the L-carnitine-treated group tended to be higher than the control group. For milk yield, the L-carnitine-treated group tended to be higher than the control group during week 1 with a decrease on the weaning day. On day 11 free L-carnitine concentrations in the L-carnitine-treated group were significantly (P<0.10) higher than that in the control group. Return of estrus tended to be earlier in the L-carnitine-treated group. The following results have been suggested : 50ppm supplementation of L-carnitine, even for short periods, positively affects the growth of piglets and return of estrus. This seemed to be due to the increase in the L-carnitine level in sow milk, and the better growth performance of piglets contributes to lessening the burden of lactation on sows.

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L-carnitine accelerates energy production in mitochondrial transport and oxidation of long-chain fatty acids. Pigs decrease sperm production activity in summer due to lower nutrition intake caused by lessened appetite in a high-temperature environment. A deterioration in semen is a serious problem especially in boars. It is presumed that L-carnitine supplementation may improve the characteristics of deteriorated semen. The present experiment compared the characteristics of semen obtained from boars in a non-treated control group and an L-carnitine supplemented experimental group, supplemented during the summer season. Semen collection was carried out twice in early and late September. Eight Duroc breed boars, 21 to 29 months old, were used. Commercial feed was given to the control group and feed supplemented with 50ppm L-carnitine to the experimental group. L-carnitine supplementation was conducted for two months from early August to late September ; semen volume, motile sperm, concentration of sperm, number of sperm, and abnormal sperm were determined at each semen collection. At the start of supplementation, motile sperm in control and experimental group were as 88.8±3% and 86.2±6%, respectively. In early September, while motile sperm was 52.5±13% in the control group, the experimental group showed a higher value (P<0.10), 86.7±3%, than that in the control group. In late September, no significant difference was found, but a tendency for higher values was maintained in the experimental group. The rate of abnormal sperm in the experimental group tended to be lower than that in the control group (P<0.10) in early September. While a significant difference was not found in other characteristics, the experimental group showed favorable sperm production values. These results suggest that the supplementation of L-carnitine maintained the normal characteristics of semen due to an increase in the reduced activity of the entire body in high-temperature environment.

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The objective of the present study was to investigate the running cost of methane fermentation by reducing urinary nitrogen excretion in pigs. Using slurry with reduced nitrogen excretion from growing-finishing pigs fed a reduced crude protein (CP) diet with apple pomace (CP : 11.6%), mesophilic methane fermentation was conducted to determine fermentation efficiency and the characteristics of the effluent. Concentrations of nitrogen and ammonia in the slurry from pigs fed a low CP diet with apple pomace were less (respectively, 13% and 34%) than those in the slurry from pigs fed the standard diet (CP : 15.3%). For the effluent from methane fermentation, the concentrations of nitrogen and ammonia for pigs fed a low CP diet were less (9% and 26%, respectively) than those for pigs fed the standard diet. By feeding a low CP diet with apple pomace, the volume of gas production from methane fermentation was 1.3 times greater than that from the standard diet. Composition of H₂S in fermentation gas from a low CP diet with apple pomace was reduced 80% compared to that from a standard diet.
In conclusion, gas energy from mesophilic methane fermentation was 1.3 times greater from a low CP diet with apple pomace than with a standard diet. The cost of removing H₂S can be decreased 70% when a low CP diet with apple pomace is used compared to the standard diet.

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[in Japanese]

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